Hole lapping tool



M arch 30, 1937. o, Q KOMMER 2,075,397

HOLE LAPPING TOOL Filed May l, 1956 I1g fa l /N VENTOR deff 46x/Affe www CTI

Patented Mar. 30, 1937 UNITED STATES PATENT OFFICE 2 Claims.

My present invention relates to improvements in cylindrical hole lapping tools and has for. its objects a more accurate adjustment than heretofore in lapping tools; second, an equal diametrical adjustment throughout the length of the lapping barrel; third, ease of adjusting for diameter of the lapping barrel; and, fourth, a positive locking of the l-apping barrel in any of its adjusted positions.

I attain these objects and others that will be apparent from a perusal of the description taken in connection with the accompanying drawing, in which:

Figure 1 is a part sectional view.

Figure 2 is a side elevation within a hole in a sleeve as when the hole is being lapped out.

Figure 3 is a sectional view taken on line A-A of Figure 1.

Figure 4 is an end View of the lapping barrel.

Figure 5 is a side view of the lapping barrel showing the expansion slots extending from expander end, and

Figure 6 is a side View of the lapping barrel at right angles to the View shown in Fig. 4 and showing the expansion slots extending from the free end of the lapping barrel.

Throughout the several views of the drawing, similar numerals refer to similar parts.

I represents a metal body and 2 a longitudinal cross-section of a cylindrical hole in which is expanded for lapping, lapping barrel 3, having expansion slots 4, as extended to wedge-like shape, to which Vshape the expansion slots 5 also are extended when the lapping barrel is expanded within the hole to be lapped out. The lapping barrel 3 is also provided with tapered inner screw threads 6 into which, to expand the lapping barrel 3, is screwedexpander member 'l having at one of its ends taper screw-threaded portion 8 and parallel threaded portion 9 onto which is screwed lock nut l0. In the outer circumference of the lapping barrel is annular semicircular groove Il having therein spring ring l2 whereby the lapping barrel is contracted on the taper threaded portion 8 of the expander 1.

In operating my hole lapping tool, the lapping barrel 3 is screwed onto the taper thread 8 until the outer diameter of the lapping barrel is just less than the diameter of the hole to be lapped out. The shank of the expander 'I is then held as by the chuck of a lathe, drill press or other allel and cylindrical to within the most minute suitable machine tool capable of imparting combined rotative and reciprocal motions to the lapping tool. The work having the hole to be lapped out is brought to the tool, the lapping barrel entered into the hole and adjusted thereto, and the lock nut I0 is turned on the threads of the threaded portion 9 securely against the end of the lapping barrel. The machine tool is started and imparts a rotative motion to the lapping tool. Very fine abrasive material as emery powder, 1o rouge and the like, together with oil is then fed to the lapping barrel which is given a reciprocal motion back and forth as well as the rotative motion. The combination of the two motions works the abrasive between the inner wall of the 15 cylindrical hole in the work and the outer periphery of the lapping barrel and the combined motions of the lapping barrel laps and polishes out the hole to an increased diameter, perfectly parmeasurement of the size desired. From time to 20 time during the lapping out of a hole, the lock` nut is loosened and the lapping barrel 3 is screwed farther onto the taper thread 9 of the expander member and again locked thereon by the lock nut o;

l0. This expanding of theg lapping barrel is repeated until the hole being lapped is of the desired diametrical dimension.

Having described my present invention, I claim: 0

1. A hole lapping tool comprisingvan expansible and contractible lapping barrel having a taper screw thread extending axially therethrough and a plurality of slots extending axially from each of its ends, an expander for said barrel having 35 a taper screw thread at one of its ends within the lapping barrel, a parallel screw threaded portion out of said lapping barrel and having an annular lock nut for locking the lapping barrel to the said expander and a contracting spring for said lapping barrel in an annular groove in the outer periphery of the said lapping barrel.

2. A hole lapping tool comprising an expansible and contractible barrel having a plurality of slots extending axially inwardly from each of its ends and a taper screw thread extending axially between the two ends and a taper screw threaded expander extending into said taper screw threads and an annular nut for locking said barrel to said expander for the purpose specified. Y

ORIE C. KOMMER. 

